Procedure and apparatus for collection of free methane gas from the sea bottom

ABSTRACT

The present invention is referring to a procedure and an apparatus for collection of free methane gas from the sea bottom, destined to collect and liquefy the methane gas liberated from metastabile deposits of hydrate methane situated on the seas or oceans bottom. The procedure, in a first version of realization, according to the invention, includes the collection of free methane gas from the sea bottom in a mixture with the sea water and directing this mixture up wards to the surface, where is taking place a gravitational distribution of it on a big surface, for permitting the methane gas to separate from water. The humid captured methane gas is cooled to produce the condensation of the last seawater fraction after, which is done its cooling to the required temperature for passing from the gaseous state into the liquid state.  
     The apparatus, in its first version of realization, according to the invention, is made from some guiding arms A on which is sitting an intermediary platform B, destined to support some electrical reversible trolleys D and E, used for the displacement on radial and vertically direction of some telescopic conduit  21  and of some collectors K, of some electrical reversible and double trolleys F for driving some separators L and of a flexible conduit  50  on radial direction, as well and of some electrical reversible and double trolleys G used for some lateral anchors  7  maneuver. On the vertical axis of apparatus is found a central anchor  5  stiffed by a hoist  4 . The ends of arms A are provided with some propellers  8, 9, 10  and  11  for ensemble&#39;s rotation. On platform B and C are positioned a humidity extractor M from which the condense is eliminated, a gas methane liquefactor N and this is connected with a storage tank O. A nitrogen compressor  70  discharged the arrived nitrogen through laminate valve f towards a tank of liquid nitrogen P

The present invention is referring to a procedure and apparatus forcollection of free methane gas from the sea bottom destined to catch andliquefy the released methane gas from metastabile of methane hydratesituated on the seas and oceans bottom.

Following the increased interest of world's wide regarding the researchefforts on getting the methane gas, a multitude of hydrate formationzones were discovered on the seas and oceans bottom bed, from which wasfound a multitude of metastabile zone of methane hydrate withoutlithologocal cover. If only a small fraction of this free methane gasfrom the seas and oceans bottom would be collected, it could constitutea significant energy resource as a fuel.

It is not known a procedure for collection of methane gas released fromzones of metastabile gas hydrate deposits from the sea bottom. It is notknown an apparatus destined to free methane gas collection released fromdeposits of hydrate gas from the sea bottom.

The matter that is resolved by the invention is the realization of aprocedure and an apparatus, which will allow the free methane gascollection from the bottom of the sea. The procedure for collection offree methane gas from the bottom of the sea, according to the invention,eliminate the above mentioned disadvantages, because it is constitutedfrom a first operation in which the collection of free methane gas fromthe bottom of the sea takes place and it is directed upwards, to arunning section of methane gas, together with the sea's water andforming a mixture of methane gas-sea water. The shifting of mixture isdone under a form of a current tube up to a room in which is takingplace the separation phase, in which the mixture overflows at a levelinferior to the sea's level, where the pressure is smaller than the oneof the sea's bottom, and where is taking place adistribution/gravitational dispersion of it on a big surface on whichthe running is done at a more reduced pressure, which allows theseparation of methane gas from water. The humid methane gas is collectedat the room's superior part and the sea water is running freely towardsan inferior level, from where, in the following operation, is absorbedand evacuated back in the sea for insuring the required level differencefor the mixture's raising. In the following operation, the humid methanegas, captured at the superior room's part, is absorbed towards an otherroom where is cooled to reduce the condensation of the last fraction ofsea's water, operation after which are obtained sea water in liquidstate which is collected and then evacuated and dry methane gas. In thefollowing operation is proceeding to the methane cooling at requiredtemperature for its passing from gaseous state into liquid state. Theprocedure, in an other version of realization, comprises a firstoperation in which the humid methane gas, brought to the sea's surfaceis cooled in a room by bringing it in contact with cooled methane gasand by mixing it with this. Due to the diminished temperature it istaking place the condensation of the last fraction of the sea's watervapors and is getting the dry methane gas.

This operation is followed by the compression, in a first stage, up to acertain pressure and temperature, after which, to an other operation iscooled at sea water temperature. Follows a second compression stage,followed by a new cooling at sea temperature and by that the third stageof compression, in a last operation the methane gas discharged afterthis last compression being sent to a room where, after laminationfollowed by an adiabatic expansion, is passing from a gaseous phase to aliquid phase.

In parallel with the above operation, an other phase occurs, in which apart of compressed methane gas in first stage is taken to produce theabsorption of liquid methane obtained according with the last operation.Following to this absorption, the compressed hot methane gas from thefirst compression stage is mixed with the liquid methane and isdischarged into a room in which is taking place a first cooling ofmethane gas arrived following the operation of its water separation. Theapparatus for collection of free methane gas from the sea bottom,according to the invention, is made from some guiding arms, set-up incrosswise position, on which are sitting an intermediary platform,destined to support some electrical reversible trolleys, used for radialand vertical direction displacement of a flexible or telescopic conduitand of some collectors for mixture, some double reversible trolleys withthe help of which some water separators and a flexible conduit can bevertically and radial driven, and the flexible conduit is supported onits horizontal portion by some floating caissons, as well and of somedouble reversible electrical trolleys used to change the position ofsome lateral anchors.

An inferior platform, together with the intermediary platform, isdestined to support the components of some technological lines, and asuperior platform serves to alight or take off for the helicopter. Somesloping portion of guiding arms serve to support the three specifiedplatforms and its superior ends are rigidly connected and keep up ahoist to stretch out a central anchor. Under each guiding arm is seatinga water separator connected at its inferior part through a telescopicconduit with the collector of mixture, and on intermediary and inferiorplatform are located corresponding to the water separators and connectedto them through the flexible conduits, the mentioned technologicallines. The guiding arms are provided with some horizontal portionssupported by some floating caissons, at the ends of each arm beinglocated some helix, so that at their putting in operation to do a couplewhich to rotate the entire ensemble around the vertical axis,materialized by the central anchor's rope. Rigidiness of the showedguiding arms is done with the help of some ropes stretched between theexterior ends of its horizontal portions. The inferior and mediumplatforms have an octagonal form and are provided with an opening. Eachof the water separators are provided with a parallelepiped corps closedat the superior part with a cover and sitting on a submarine platformsustained by some floating caissons. Inside is placed an horizontalplate which defines an inferior and superior room, on plate beingmounted an overflow sleeve, connected at its down end to a telescopicconduit and some guiding tubs through which vertical is running theropes through which is achieving the supporting of telescopic conduitand the mixture collector.

At the superior part of parallelepiped corps are sitting some screensfor separation and on the same submarine platform are also sitting somepumps for evacuation. The hanging up of water separator is realizedthrough some ropes, time in which the seating of mixture collector closeto the sea bottom is done through some legs. Each of technological linesis provided with an extractor of humidity from methane, connected to thebottom with a conduit through which the condensate is eliminated andupper part, through other conduit, the dry methane gas is passingtowards a methane gas liquifier, from which is running in the liquidstate through a conduit in a storage tank. A compressor for nitrogendrive the nitrogen in gas state through a valve of lamination towards atank of liquid nitrogen from where, the becoming liquid nitrogen isrunning towards some serpentines of methane liquidifier and respectivewater extractor. The turbo compressor is driven by a turbine with gases,which is driving and an electrical generator also. The reversibleelectrical trolleys are provided with some ropes supported and guidedwith the help of some guiding rolls and of one block of rolls. Theapparatus, in an other version of realization, is provided with an othertechnological line equipped with an other extractor of humidity,connected through a conduit to the water separator, which is placed onan inferior platform and connected through other conduit to someturbocompressor in steps. They are situated on the same axis of aturbine with gases, which is coupled with an air compressor, and with anelectrical generator, between turbocompressors being inserted somecoolers. The turbocompressor is connected through a conduit with a tankof liquid methane provided with a valve for lamination, between thewater extractor and the liquid methane tank being placed an ejector inwhich the aspiration is realized through a conduit through which themethane gas is brought from turbocompressor.

By using the invention, the following advantages are acquired:

-   -   The use of a big source of combustible which will reduce the        effect of the energy needs.    -   The diminution of the atmosphere pollution.

In the following is presented an example of invention's realization inconnection with figures from 1 to 10, which represent:

FIG. 1, general lateral view of apparatus for collection of free methanegas from the bottom of the sea, according to the invention;

FIG. 2, the kinematics sketch for driving anchors collectors and ofmethane gas separators, afferent to each guiding arms, according withthe invention;

FIG. 3, the technological line of methane gas liquefaction, in firstversion of realization, afferent to each guiding arm, according to theinvention;

FIG. 4, lateral view of apparatus, according to the invention, makingevident the connection between the collector and separator of methanegas and technological line afferent to a guiding arm;

FIG. 5, section with a plane I-I from FIG. 4;

FIG. 6, section with a plane II-II from FIG. 4;

FIG. 7, section with a vertical plane through the collector and throughthe methane gas separator;

FIG. 8, section with a horizontal plane III-III from FIG. 7;

FIG. 9, section with a vertical plane IV-IV from FIG. 8;

FIG. 10, the technological line of methane gas liquefaction, in otherversion of realization, afferent to each guiding arm, according to theinvention.

The procedure for collection of free methane gas from the sea bottom, ina first version of realization, according to the invention, starts witha first operation in which is taking place the collection of saturatedmixture formed from sea water and methane gas and of free methane gasemanated from metastabile deposits from the sea bottom, from a bigsurface and of them upwards direction to a narrow running sectiontowards sea's surface.

The water-methane gas mixture, which is rising continuously from the seabottom based on the vessels communication principle, is over flown, inthe next phase in a room, at an inferior level of the sea's level, wherethe pressure is smaller than that from the sea bottom and where istaking place a gravitational distribution/spreading of it on a bigsurface on which the running is done on a thin stratum. In theseconditions, the separation of methane gas and water is done, the humidmethane gas is collected at the superior part of room and the sea wateris running freely towards an inferior level from where, in the nextoperation, is sucked and evacuated back into the sea.

The humid methane gas is then cooled, in an other room, by being incontact with a continuous cooled surface, for the condensation of thelast fraction of the sea water vapors to be done, operation after whichis obtaining the dry methane gas and sea water in liquid state, waterwhich is collected and then evacuated.

In the next operation the cooling of methane gas is continued, until therequired temperature for its passing into the liquid state is achieved,followed by its collection and storage.

The procedure for free methane gas collection from the sea bottom inother version of realization, according to the invention, is showing themodality of liquefaction of methane gas by compression and lamination,followed by an adiabatic expansion. In this way, the humid methane gasbrought to the sea surface is cooled in a room by bringing it in contactwith a jet of cooled methane gas and by mixing this cooled gas inside ofthe mentioned room. Because of temperature reduction is taking place thecondensation of last fraction of sea water vapors, operation after whichis obtained dry methane gas and sea water, water which after collectionis evacuated.

The dry methane gas is sucked and compressed in a first step, up to acertain pressure and temperature, after which, in an other operation, isbrought under the sea level where in contact with a surface at seatemperature is taking place its cooling.

These two successive operations of compression and cooling of methanegas are repeated also in the second step of compression. The methane gasso compressed at this second step is cooled too at the sea temperatureand then is compressed again in that of the third step.

In a last operation, the methane gas discharged after the thirdcompression is sent to a room where, after a lamination followed by anadiabatic expansion, is passing from gaseous phase into liquid phase.

In parallel with the above described operation of procedure, accordingto the invention, in this second version of realization, is taking placean other phase, in which a part of compressed methane gas from firststep is taken to produce the suction of liquid methane gas obtainedaccording to the last operation. The sucked liquid methane is dischargedinto the mixture with gaseous methane from the first step of compressiontowards a room in which, as was shown before, is taking place the firstcooling of methane gas coming from water separator.

The apparatus for collection of free methane gas from the sea bottom, ina first version of realization, according to the invention is made fromsome guiding arms A positioned crosswise and provided with a horizontalportion 1 maintained at sea surface level with the help of some floatingcaissons 2 and which is cotinuing in the central zone with a sloppingportion 3. The floating caissons 2 should be able to take over thestatics and dynamics loads caused by the waves and winds so that theapparatus, according to the invention, to be maintained at sea surfacelevel.

The slopping 3 portions are rigidified between them at the superiorportion and holding a hoist 4 for stretching a central anchor 5, asuperior platform 6 destined to alight and take off of helicopters, anintermediary platform B and an inferior platform C which sustain thepower actuated elements and other various equipment.

The guiding arms A can be made from steel pipes, assembled in lattices,and the platforms 6, B and C are provided with steel grills and withbalustrades for service personnel's protection. The platforms 6, B and Chave to be rigidified towards the sloped portions 3 with the help ofsome beams, pillars, bars and diagonals, but these construction detailsdo not make the object of this invention, being themselves known.

In the same time, the platforms B and C which have an octagonal shapeand each are provided with an opening a and respectively b, will beplaced at a sufficient height so that the sea's waves action to notimpeded the worker's activity and the function of the equipment situatedthe platforms.

Because this entire apparatus, according to the invention, not to bedisplaced by the sea's currents of waves and winds, it is provided,besides the central anchor 5 with some lateral anchor 7, one for eacharm A, connected by ropes.

The apparatus, according to the invention, can be rotated on anhorizontal plane, around of central anchor 5, with the help of somepropellers 8 and 9, driven by some not shown electromotrs, propellersplaced diametrical opposite to the exterior ends of two arms A with thepurpose of producing a couple of rotations of the entire ensemble.

The braking of this rotation movement can be done with the help of someother propellers 10 and 11 placed at the exterior ends of the other twoarms A, diametrically opposed, allowing in this way to choose thedesired position of the ensemble. It is obviously understood that,during the rotation operation of apparatus, according to the invention,the lateral anchors 7 should be raised.

To obtain a good stiffness of the guiding arms A, the exterior ends areconnected between them with some ropes 12.

On the intermediary platform B are placed some groups of electricalreversible trolleys D, E, F and G, placed over each of guiding arms Aand destined for driving the suspended components of respective arm A.On platform B is also placed a part of the necessary equipment of atechnological line H.

The first two trolleys D and E are provided with a rope 13 andrespectively 14, which are running on some guiding rolls 15 and 16 andrespectively 17 and 18 as well and on a roll 19 and respectively 20,placed on a rolls block J, the ropes 13 and 14 upholding and permittingthe vertical position modification of a collector K of mixture and of aconduit 21.

The third electrical reversible and double trolley F id driving a rope22 which is passing over some guiding rolls 23, 24 and connected withframe 25 placed on block J, from where an other rope 26 is rolling on aguiding roll 27, then on a guiding roll 28 placed on block J and on someguiding rolls 29 and 30, rope 26 which allows the radial displacementalong the arms A, of block of rolls J of a water separator L.

The trolleys G also double, is driving a rope 31 which is rolling onsome rolls 32 and 33, on a roll 34 placed on block J and then on aguiding roll 35 being connected at the inferior end of lateral anchor 7and permitting its vertical movement.

An other rope 36 of the same trolley G is rolling on some guiding rolls37 and 38 with the scope of radial displacement and anchoring to thebottom of the sea the lateral anchor 7.

The water separators L are placed under each of guiding arms A, beingpartially submersed in the seawater.

Each of the water separators L are provided with a parallelipipedic body39 closed tight and provided at its superior part with a cover 40, likea pyramid. The body 39 includes a superior room c in which are providedsome horizontal strainers 41 and 42 of different sizes which are placedat certain distance one to the other, with the purpose of contributingto the partial separation of the methane gas of water vapors.

In the center of the body 39 is placed an overflow sleeve 43 united witha horizontal plate 44 so that the superior end of sleeve 43 to besituated under the seawater surface level and in the same time, over theplate 44. The bottom of the body 39 is placed on a platform 45;platform, which is sitting on some floating caissons 46 and togetherwith plate 44, forms an inferior room d.

The sea water-methane gas mixture, which is running from sleeve 43 andis spreading on plate 44 surface, liberates the gas and the water isrunning through the two ends of plate 44 entering in the inferior roomd. Some pumps 47 placed close to the body 39 on the same platform 45suck the water from room d and discharge it in the sea.

The superior corners of paralelipipedic body 39 are connected with thehelp of rope 48 by the rolls block J, connection that allows the waterseparator L to move on a radial direction.

The overflow sleeve 43 is connected at its inferior ends with conduit21, which can be flexible or telescopic and of which the inferior endwas connected to the collector K. This one has the form of a pyramid andis provided at its base perimeter with some sitting legs 49 of a certainweight. After the collector K positioning over a metastabile zone e ofhydrate methane, by penetration its legs 49 in the stratum of the seabottom, its anchorage in a chosen position should be achieved.

The water separators L are connected to some aerial flexible conduits 50of which horizontal portions found under the arms A are sitting on somefloating caissons 51.

The ropes, 13 and 14, which are upholding the collector K, and conduit21, are crossing the body 39 of separator L through some guiding tubes52.

At its superior part, aerial, each flexible conduit 50 is connectedthrough a fixed conduit 53 and a valve 54 with some humidity extractor Mlike a heat exchanger, located on an intermediary platform B. Theextractor M is provided with a cooling serpentine 55, connected throughvalves 56 and 57 with technological line H, with a valve 58 at itssuperior part and with a discharge valve 59 at its lower part. From thevalve 58 through conduit 60 and a valve 61 the extractor M is connectedwith a liquefactor of methane gas N equipped with an other coolingserpentine 62, provided at its ends with some valves 63 and 64 forentering and respectively exit.

The humidity extractor M and the gas liquefactor N are located on theintermediary platform B.

At the lower part of the liquefactor N are sitting a discharge valve 65which, through a conduit 66 and a valve 67 makes the connection to astorage tank O provided with a discharge valve 68, and sitting on aninferior platform C.

The serpentine 55 of the extractor M is connected through a returnconduit 69 to a compressor for nitrogen 70 driven by a gas turbine 71.The closing of this line through which the nitrogen is running is donethrough a discharge conduit 72 which makes the connection to a tank ofliquid nitrogen P provided at its superior part with a valve 73 and alamination valve f for adiabatic nitrogen expansion, and at the lowerpart with an other valve 74 from which through conduit 75 and entrancevalve 63 is done the connection with gas liquefactor N.

The exit valve 64 of the cooling serpentine 62 of liquefactor N can beconnected, either with the entrance valve 56 of serpentine 55 ofextractor M through a conduit 76, or with a return conduit 69 through aconduit 77 and a valve 78.

An other connection, done with the scope of apparatus air purging,according to the invention, is that through which the conduit 60 betweenthe valves 58 and 61 of extractor M and respectively liquefactor N wasconnected with the discharge conduit 72 which connects the compressor 70with entrance valve 73 and the lamination valve f of liquid nitrogentank P, connection made through a conduit 79 and a purge valve 80.

An other conduit 81 and a valve 82 make the connection from the superiorpart of liquid nitrogen tank P and the return conduit 69, on which isprovided a connection 83 for filling with nitrogen gas.

The required electric energy for supplying the electromotors and otherelectrical subensembles of apparatus, according to the invention, isfurnished by some electrical generators 84 placed on each of the guidingarms A and driven by gas turbine 71.

The apparatus for collection of free methane gas from the sea bottom, inan other realization version, according to the invention, has as scopethe liquefaction of methane gas by compression, goal achieved with thehelp of a technological line Q. The coming methane gas from waterseparator L through conduit 53 enters through valve 54 in a humidityextractor R placed on platform C.

The dry methane gas is sucked through a valve 85, a conduit 86 and thenthrough a valve 87 of a turbocompressor S, placed on the guiding arm A,from where, after a first compression, is sent through a valve 88 andconduit 89 to run through a cooler g placed in the sea water at a levelclose to its surface. From the cooler g, the methane gas is suckedthrough conduit 90 and through a valve 91 by turbocompressor T situatedon the same axis with turbocompressor S. In the compressor T takes placethe second step of methane gas compression and from where is dischargedthrough a valve 92 and a conduit 93 towards an other cooler h, situatedin the same conditions like the cooler g under the sea's surface level.

After the second cooling operation the methane gas is sucked through aconduit 94 and through valve 95 by the compressor U which does the thirdstep of compression before the liquefaction. From here, the methane gaspasses through valve 96 a conduit 97 a valve 98, after which is laminatethrough a valve j and then is adiabatic expanded passing in the liquidstate in a tank V, where is being accumulated. From the tank V theliquid methane can be delivered to the custumers through conduit 99 andvalve 100.

The turbocompressor S, T and U are driven by a gas turbine W coupledwith an air compressor Z and with an electrical generator 84, all theseequipment being placed on the guiding arm A at the intersection betweenthe horizontal portion 1 and the sloping portion 3.

The cooling and condensation of water vapors from the humidity extractorR is done by sucking through a valve 101 and conduit 102 with the helpof an ejector m the liquid methane from the tank V and then introducingit through a conduit 102 in the humidity extractor R in a gaseous stateand at a suitable temperature for cooling and condensing the watervapors arrived with the gaseous methane through conduit 53 and valve 54.The condensate evacuation is done through a conduit 104 and valve 105.

The transformation of methane from liquid state in a gaseous state takesplace in the ejector m with the help of hot methane gas arrived throughvalve 106, a conduit 107 and through an other valve 108 from theturbocompressor S.

The use of technological line Q for the methane liquefaction requires anadditional attention and safety protection in order to eliminate thepossible methane explosion.

Like in the case of other apparatus components, according to theinvention, on each from guiding arms A and on platforms B and C isinstalled a technological line Q.

The apparatus, according to the invention, can be brought at theprospective place, where the methane collection will take place, bytowing or propelling, or unensembled and then ensembled above themetastabile hydrate gas deposit of which extraction follows.

After its positioning at the desired coordinate by putting it inoperation two by two and as much as it is necessary the propellers 8, 9,10 and 11, it is proceeding to the ensemble alighting, letting first thecentral anchor 5 with the help of hoist 4 and then on row as two fromlateral anchors 7 placed diametrically opposite, with the help of ropes31 and 36 and the electrical reversible and double trolleys F and G.

The apparatus, according to the invention, once it is positioned, thetrolleys D and E are put in operation, choosing first the position on aradial direction of water separators L the mixing collectors K andrespectively a flexible conduit 50, maneuver followed by launching thecollectors K and conduit 21 until near of the sea bottom, following agood set of legs 49 for giving stability to the collectors K.

The pumps 47 are put in operation to suck the water from the inferiorroom d of water separator M, water which is accumulated here after themixture of sea water-methane gas overflows from sleeve 43 and for itscontinues evacuation into the sea. In this way it is ensured andcontrolled a water level, inferior of the upper end of mentioned sleeve43.

This fact allows, in the first place, the ascendant flow of seawater-methane gas mixture, which is coming from metastabile zone ethrough collector K and conduit 21. This level difference facilitatesalso the water distribution on the entire surface of the horizontalplate 44 for taking place the gravitational separation, due to thedifference of the density of methane gas and seawater.

The humid methane gas collected at the superior part of room c is suckedby conduit 53, enter into the humidity extractor M, where, due to theserpentine 55 cooled with nitrogen, is taking place the water vaporscondensation on this surface and then the water collection and itsevacuation through a connection 86 and a valve 59. The dry methane gasgoes out from the extractor M through valve 58 and conduit 60,penetrates through valve 61 and enters into the methane liquefactor N,in which is produced its cryogenic liquefaction, due to the contact withthe cooling serpentine 62 through which is running nitrogen.

The liquid methane accumulated at the inferior part of liquefactor N isrunning through valve 65 and 67, conduit 66 entering into the storagetank 0, from where its evacuation is done through connection 87 andvalve 68.

The required nitrogen to the liquefactor N and the extractor M isintroduced in apparatus, according to the invention, in gaseous statethrough connection 83, the return conduit 69 towards the compressor 70,from where is discharged through conduit 72, valve 73 and laminationvalve f, where takes place the adiabatic expansion and then in theliquid nitrogen tank P. From here, the liquid nitrogen is runningthrough the exit valve 74, Bibliographic References Patents: 4,007,787February 1977 Cottle & Al. USA 4,376,462 March 1983 Elliott & Al. USA4,424,858 January 1984 Elliott & Al. USA 6,180,843 January 2001 Heineman& Al. USA 6,192,691 Februay 2001 Nohmura & Al. USA-Japan 6,209,965 April2001 Borns & Al. USA 6,214,175 April 2001 Heineman & Al. USA 6,299,256October 2001 Wyatt & Al. USA Technical literature “Hydrate ofHydrocarbons” by Yury Makogon, Editor Penn-Well Books, Tulsa-Oklahoma,USA 1977.

1. Procedure for the collection of free methane gas from the sea bottom,characterized by means of that, in a first operation takes place thefree methane collection from the sea bottom and it is directed up wards,to a running section of methane gas together with sea water and forms amixture of methane gas and sea water. The displacement of mixture isbeing done under the form of a current tube until a room in which takesplace the separation phase, in which the mixture overflows, at aninferior sea level, where the pressure is smaller then that from the seabottom and where takes place a distribution/gravitational spreading ofit on a big surface, on which the running is done at a lower pressure,to permit the separation of methane gas from water, the humid methanegas being collected at the superior part of the room, and the sea waterfreely running to an inferior level from where, in the followingoperation, is sucked and evacuated back in the sea to ensure therequired level of difference for mixture's rising, and in the followingoperation the humid methane gas, captured at the superior part of theroom, being sucked to an other room, where it is cooled to produce thecondensation of last sea water fraction, operation after which isobtained sea water in liquid state, which is collected and then isevacuated and dry methane gas, in the following operation, proceeds tothe cooling of this gas at a required temperature for it to pass in theliquid state.
 2. Procedure for the collection of free methane gas fromthe sea bottom, in an other version of realization, characterized bymeans of that, in a first operation, the humid methane gas brought tothe sea surface, is cooled in a room by bringing it in contact with coolmethane gas and by mixing it with that, due to the temperature loweringtakes place the condensation of the last fraction of sea water vaporsand obtaining of the dry methane gas, the operation followed by itscompression in a first step, up to a certain pressure and temperature,after which, in an other operation, is cooled at the seawatertemperature, after which takes place a second step of compressionfollowed by a new cooling at the sea water temperature and of the thirdstep of compression, an a last operation the methane gas is dischargedfollowed by this last compression and sent towards a room where, afterthe lamination followed by an adiabatic expansion passes from thegaseous phase into the liquid phase. In parallel with the aboveoperation takes place an other process in which part from compressedmethane gas in first step is taken for producing the suction of liquidmethane obtained, according to the last operation, sucktion after whichthe compressed and warm methane gas from the first step of compressionis mixed with the liquid methane and is discharged into a room in whichtakes place a first cooling of methane gas arrived as a result of itswater separation operation.
 3. Installation for free methane gascollection from the sea bottom, characterized by means of that, in afirst realization operation, is constituted from some guiding arms A ina crosswise position, on which are sitting an intermediary platform B,destined to support some electrical reversible trolleys D and E used fordisplacement on vertical and radial direction of a flexible ortelescopic conduit 21 and of some collectors K of some electricalreversible and double trolleys F with the help of which some separatorsL and a flexible conduit 50 can be driven on a radial direction, andconduit 50 can be driven on radial direction, and conduit 50 is kept inits horizontal position by some floating caissons 51 as well and of someelectrical reversible and double trolleys G used to modify the positionof some lateral anchors 7 and an inferior platform C destined forsupporting together with platform B of components of a technologicalline H or Q and a superior platform 6 for alight or take-off ofhelicopter, some sloping portion of arms A serving for installingmentioned platforms B, C and 6 and the superior ends of them beingrigidly assembled and supporting a hoist 4 for stiffing of a centralanchor
 5. 4. Apparatus for free methane gas collection from the seabottom, according to the claim 2, characterized by means of that, underof arm A is placed a separator L connected at its inferior part througha conduit 21 to the collector K and on platform B and C are placedaccordingly the separators L and connected with them by intermediary offlexible conduit 50 the mentioned technological lines H or Q. 5.Apparatus for collection of free methane gas from the sea bottom,according to the claim 2 characterized by means of that, the guidingarms A are provided with some horizontal portions 1 supported by somefloating casings 2, at the exterior ends of each from arms A beinglocated some propellers 8, 9, 10 and 11 so that at theirs putting inoperation to produce a couple which to rotate the apparatus, accordingto the invention, around a vertical axis, materialized by rope ofcentral anchor 5, the stiffness of mentioned arms A being done with thehelp of some ropes 12 stretched between the exterior ends of horizontalportion
 1. 6. Apparatus for collection of free methane gas from the seabottom, according to the claim 2, characterized by means of that theplatform B and C have an octagonal form are provided with some openingsa and respectively b.
 7. Apparatus for collection of free methane gasfrom the sea bottom, according to the claim 2, characterized by means ofthat, each from water separators L is provided with a parallelepipedbody 39 closed at its superior part with a cover 40 and sitting on aplatform 45 supported by some floating cassias 46, in interior beingpositioned an horizontal plate 44 which delimits some rooms c and d andon which are installed a sleeve for overflow 43 connected at itsinferior end with conduit 21 and some guiding tubes 52 through whichvertically is running the ropes 22 and 26 through which are supportedconduit 21 and a collector K, and at superior part of body 39 beinginstalled some screens 41 and 42, on the same platform 45 beingpositioned and some pumps 47, and the connection of separator L is doneby some ropes
 48. The positioning of collector K close to the sea bottomis done with some legs
 49. 8. Apparatus for collection of free methanegas from the sea bottom, according to the claim 2, characterized bymeans of that, each form the technological lines is provided with anhumidity extractor M connected at its base with conduit 50 and fromwhich is eliminated the condense from the methane gas, and at superiorpart by the conduit 60 the dry methane gas passes towards a methane gasliquidifier N from which is running, in the liquid state, throughconduit 66 in a storage tank 0, a nitrogen-compressor 70 discharging thenitrogen gas through the expanded valve f towards a liquid nitrogen tankP from where the nitrogen is running towards some serpentines 62 and 55of liquefactor N and respectively extractor M turbocompressor 70 beingdriven by a gas turbine 71 which is driving also an electric generator4.
 9. Apparatus for collection of free methane gas from the sea bottom,according to the claim 2, characterized by means of that, the electricalreversible trolleys D, E, F and G are provided with some ropes 13, 14,22, 26, 31 and 36 supported and guided with the help of some rolls 15,16, 17, 18, 19, 20, 23, 24, 25, 27, 28, 29, 30, 32, 33, 34 and 35 and ofa block of rolls J.
 10. Apparatus for collection of free methane gasfrom the sea bottom, characterized by means of that, in an other versionof realization, is provided with a technological line Q equipped with anextractor of humidity R connected through conduit 53 to the separator Lsituated on platform C and connected through a conduit 86 at someturbocompressor S, T and U installed on the same axis of a gas turbine Wwhich is coupled with an air compressor Z and with an electricalgenerator 84, between turbocompressor S, T and U being inserted somecoolers g and h, the turbocompressor U being connected through a conduit97 with a methane liquid tank V provided with a laminate valve j,between the extractor R and the tank V being placed an ejector m inwhich the suction is realized through a conduit 107 trough which isbrought the methane gas from compressor S.